Dishwashing machines



F. w. ROBSON ETAL 3,221,754

DISHWASHING MACHINES 4 Sheets-Sheet 2 N 8 MO Y 08 E MW L e m H N W T I Ammwm/ Dec. 7, 1965 2 mm mm 1 J L\ m U/% 4 Ongmal Flled Dec Dec. 7, 1965F. w. ROBSON ETAL 3,221,754

DISHWASHING MACHINES Original Filed Dec. 5, 1962 4 Sheets-Sheet 5PREWASH Fl% 6 RED 9| SOLENOID NZ RINSE SOLENOID 52a "'6 -k4aa -|5a- 4s ma g 7.... .m. '7 I 7 4% 3 52a 2* T '4 Il7/qll6 INVENTORS ua l FREDERICKw. ROBSON BYWlLLlAM A. WAHL F mazmwj w Mew Dec. 7, 1965 w. ROBSON ETAL3,221,754

DISHWASHING MACHINES Original Filed Dec. 5, 1962 4 Sheets-Sheet 4INVENTORS. FREDERICK W. ROBSON WILLIAM A. WAHL mm 3n ATT RNEYS UnitedStates Patent Ofi 3,221,754 Patented Dec. 7, 1965 3,221,754 DISHWASHINGMACHINES Frederick W. Robson and William A. Wahl, Rochester, N.Y.,assignors to Toledo Scale Corporation, Toledo,

Ohio, a corporation of Ohio Continuation of application Ser. No.242,536, Dec. 5, 1962. This application Sept. 28, 1964, Ser. No. 402,686

4 Claims. (Cl. 134-68) This application is a continuation of US.application Serial No. 242,536 filed December 5, 1962, now aban- $13115?in names of Frederick W. Robson and William A.

This invention relates to conveyor dishwashing machines.

The principal object of this inventionis to arrange conveyor dishwashingapparatus to so complement two dish tables that the path of travel ofdishes to, through and from the apparatus is in the shape of a U.

Another object of the invention is to so arrange the above apparatusthat dish racks are fed into the apparatus from one of the tables andout of the apparatus onto the other table without need for an operatorto lift the racks into or out of the apparatus.

Still another object is to provide an L-shaped conveyor dishwashingmachine which can be operated by one man standing between tables infront of the machine.

A further object is to provide the above L-shaped machine with means forconverting it from a front fed and unloaded machine to an end fed andfront unloaded machine.

Another object is to provide an improved conveyor system for dishwashingmachines.

Still another object is to provide, in a dishwashing machine, twoconveyors, one for carrying dishes partly through the machine and theother for carrying dishes through the rest of the machine and out of themachine, and an automatic timing system for keeping such conveyors insynchronism.

A further object is to provide, in a dishwashing machine, a timingsystem for a continuously running conveyor and an intermittently runningconveyor which is remotely located relative to the conveyors.

Another object is to provide an automatically operated, L-shapedconveyor dishwashing machine.

Still another object is to provide, in a dishwashing machine, twoconveyors at right angles to each other with automatic transfertherebetween.

A still further object is to provide improved automatic control systemsfor dishwashing machines.

Another object is to make conveyor dishwashing machines more convenientfor the operators to use.

One embodiment of this invention enabling the realization of theseobjects is an L-shaped conveyor dishwashing machine which can beoperated by one man standing between tables in front of the machine, thepath of travel of dishes to, through and from the machine being in theshape of a U. Two conveyors are provided at right angles to each otherone in each leg of the L-shaped machine to carry racks of dishes throughthe machine. The operator feeds racks of dishes from the front of themachine to a continuously running one of the conveyors which carries theracks through conventional prewash, power wash and power rinse areaswhereupon the racks are transferred automatically to an intermittentyrunning one of theconveyors which carries the racks through aconventional final rinse area and out of the front of the machine ontoone of the tables. An automatically operated timing system is providedwhich turns the prewash and the final rinse on and off, starts and stopsthe intermittently operated conveyor and operates signals and/or stopmeans in accordance with when the machine can be fed all in properlytimed sequence. The timing system is remotely located relative to theconveyors.

In accordance with the above, one feature of this invention resides inthe saving of labor cost by the operation by one man standing in frontof the machine.

Another feature resides in saving valuable space at both ends of themachine by feeding and unloading from the front.

Still another feature resides in arranging the two tables so that theoperator can push dish racks from one of the tables into the machine andso that the machine delivers the dish racks out onto the other table allwithout need for the operator to lift the racks into and out of themachine.

A further feature resides in the remote location of the timing system.This facilitates locating the system in a dry place.

Another feature resides in the automatic transfer between conveyors andthe automatically operated timing system which turns the prewash and thefinal rinse on and oif, starts and stops the intermittently operatedconveyor and operates signals and/or stop means in accordance with whenthe machine should be fed. This produces an automatic, economical, safe,and easily operated machine.

The above and other objects and features of this invention will beappreciated more fully from the following detailed description when readwith reference to the accompanying drawings wherein:

FIG. 1 is a perspective view of a dishwashing machine embodying theinvention, lower panels being removed to reveal otherwise hiddenstructure;

FIG. 2 is a fragmentary, horizontal sectional view taken at about themiddle of the machine shown in FIG. 1 looking down at the machine;

FIG. 3 is a vertical sectional view taken along the line 33 of FIG. 2;

FIG. 4 is a diagrammatic view illustrating the operation of the machineshown in FIG. 1;

FIG. 5 is an enlarged, fragmentary, elevational View of one of thevertical endless conveyor chains shown in FIG. 4;

FIG. 6 is a schematic drawing of an electrical circuit for the automaticcontrol of the machine shown in FIG. 1;

FIG. 7 is a fragmentary view corresponding to the right hand portion ofFIG. 2 showing a modified machine;

FIG. 8 is a vertical sectional view taken along the line 88 of FIG. 7;and

FIG. 9 is a perspective view of the machine shown in FIG. 1 taken from adifferent angle illustrating work tables operative in conjunction withthe machine.

Referring to the drawings, a conveyor dishwashing machine embodying theinvention includes an L-shaped cabinet 10 with an entrance 11 openingfrom the front in the long leg 12 of the L and an exit 13 also openingfrom the front in the short leg 14 of the L. The long leg 12 of the Lincludes, in succession, a pro-wash space 15, a power wash space 16, anda power rinse space 17, and the short leg 14 of the L includes a rinsespace 18. Flexible curtains 19 and 20 close the entrance and the exit,respectively. Access to the power wash space '16 and to the power rinsespace 17 is obtained through a door 21 in the side of the cabinet 10.

Liquid is supplied to sets of wash spray tubes in the power wash space16 and to sets of rinse spray tubes in the power rinse space 17 whichspray tubes are not shown, but are shown in US. Patent No. 2,746,466,issued May 22, 1956 to J. DpClague and A. W. Haas. Motor driven pumps 22supply liquid from a wash tank and a rinse tank to the wash tubes andthe rinse tubes, respectively,

which tanks are not shown, but are shown in the above patent. Thisprovides a conventional recirculating wash and rinse for the machine.Manually operated start wash button 23 and stop wash button 24 controlthe wash mechanism. Manually operated start rinse button 25 and stoprinse button 26 control the rinse mechanism. The recirculating powerwash and rinse runs continuously during continuous operation of themachine. Because it is a recirculating system, no detergent-containingwash water or hot rinse water is wasted by this procedure. Sprayingliquid in the several spaces is prevented from significantly comminglingby means of partitions as shown in the above patent.

Fresh hot water from a source outside of the machine is supplied underpressure to rinsing and sanitizing devices in the rinse space 18 whichdevices are not shown, but are shown in the above patent, such hot rinsewater being turned on and off automatically by means of a rinse solenoid27 (FIG. 6). Fresh water from a source outside of the machine also issupplied to pre-wash devices 200 in the pre-wash space 15 which areshown and described in the above patent, such pre-wash water beingturned on and off automatically by means of a pre-wash solenoid 28 (FIG.6). There is a pre-wash device 200 below and one above articles to bewashed when they are in washing position in the machine, only one of theprewash devices being seen in FIG. 2. Scraps are disposed of in a heavyduty disposer 29 located below the prewash space 15, the disposer beingcontrolled by manually operable start disposer button 30 and stopdisposer button 31. The temperatures of the water controlled by -therinse solenoid 27 and the pre-wash solenoid 28 are indicated bythermometers 32 and 33, respectively, atop the cabinet 10. Cabinet panel34 can be removed to convert the machine from front feed to end feed ifso desired. However, the machine will be described as one whereinfeeding and unloading are accomplished from the front.

The L-shaped cabinet 10 has its entrance 11 and exit 13 both openingfrom the front to so complement two dish tables 35 and 36 (FIG. 9) thatthe path of travel of dishes in racks 37, one of which is shown in FIG.4, to, through and from the cabinet 10 is in the shape of a U. TheL-shaped conveyor dishwashing machine can be operated by one manstanding between the tables 35 and 36 in front of the machine. Thissaves labor cost. Also, such feeding and unloading from the front savesvaluable space at both ends of the machine. The table 35 is the soileddish table; it includes a set down area 38 for soiled dishes, a storageshelf 39 for dish racks, a sink 40, and a work area 41 where theoperator standing between the tables loads the cleared articles to beWashed into racks and then pushes the racks into the entrance 11. Thetable 36 is the clean dish table; it includes a work area 42 whichreceives the dish racks as they are pushed out of the machine, a sortingshelf 43, and a dish soak container 44. The heights of the table workareas 41 and 42 are such that dish racks are fed into the machine fromthe soiled dish table 35 and out of the machine onto the clean dishtable 36 without need for the operator to lift the racks into or out ofthe machine.

The cabinet 10 supports a threshold channel 45 having its flangesdirected downwardly, two transversely extending angles 46 and alongitudinally extending angle 47 which angles are arranged as shown inFIG. 2 to form tracks on which the operator slides the dish racks intothe machine. Flat transverse members 48 are supported on an upper edgeof the above wash tank and form with the threshold channel 45 and theangles 46 and 47 a rectangularly shaped entrance frame as viewed in FIG.2 upon which the dish racks are placed when they are first fed into themachine, the end of the angles 46 being spaced from each other toprovide room for an idler sprocket 49 and the ends of the members 48being spaced from each other to provide room for an endless conveyorchain 50. The idler sprocket 49 is mounted for rotation by means of ashaft 51 journaled in two spaced-apart brackets 52 extending from therespective inner wall of the cabinet 10.

The dish rack tracks provided by the rectangularly shaped entrance frameare extended in the longitudinal direction by means including twochannels 53 which have their flanges directed toward the respectivecabinet walls and which are supported on the tops of the above rinse andwash tanks. The channels 53 each supports an angle 54 and eachchannel-angle pair journals a series of rollers 55 in a straight rowalong a cabinet side and at an elevation such that dish racks pushedfrom the rectangularly shaped entrance frame to the left as viewed inFIG. 2 are received on the rollers 55 for free movement therealong.

The dish rack tracks provided by the rollers 55 are extended by means ofa rectangularly shaped transfer frame 56 which includes two angles 57supported by the cabinet and extending longitudinally relative to thelong cabinet leg 12, an angle 58 supported by the cabinet and extendinglongitudinally relative to the short cabinet leg 14, two flat members 59supported atop the above rinse tank and extending longitudinallyrelative to the short cabinet leg 14, and two flat members 60 one fixedto one of the members 59 and the other fixed to the channel 58 and bothextending longitudinally relative to the long cabinet leg 12. The angles57, members 59 and members 60, respectively, have their ends spacedapart from each other as shown in FIG. 2 for purposes hereinafterdescribed. Dish racks pushed to the left as viewed in FIG. 2 arereceived upon the transfer frame 56.

The dish rack tracks provided by the transfer frame 56 are extendedthrough the short cabinet leg 14 by means including a series of rollers61 which are mounted for rotation in the same manner as are the rollers55, i.e., on suitably supported channels 62 and angles 63. Dish rackspushed into the short cabinet leg 14 from the transfer frame 56 arereceived on the rollers 61 for free movement therealong. Continuedmovement of the dish racks causes their discharge onto the clean dishtable 36 (FIG. 9).

Two endless conveyor chains at right angles to each other are providedwith automatic transfer therebetween. The first chain 50 extends throughthe long cabinet leg 12 and runs around the idler sprocket 49 and adrive sprocket 64 which is rotatably mounted by means of a shaft 65journaled in brackets 66 carried by the respective angles 54. The secondchain 66 extends through the short cabinet leg 14 and runs around anidler sprocket 67, which is rotatably mounted by means of a shaft 68journaled in brackets 69 extending from the respective cabinet wall, anda drive sprocket 70, which is rotatably mounted by means of a shaft 71journaled in brackets 72 extending from the respective cabinet Walls.The drive chains 50 and 66 are of conventional construction, one beingshown in FIG. 3 as comprising links 73 spaced apart by rollers 74, andare identical, except chain 50 includes 150 pairs of links and chain 66includes 102 pairs of links. A chain guide 75 is provided for the upperflight of the chain 50 and includes a channel 76, shown in detail inFIG. 3, and a bar 77 (FIG. 3) on which the chain rollers 74 run. Thechain guide channel 76 is fixed to the spaced apart ends of the flatmembers 48, to the spaced apart ends of the flat members 59, and to asimilar chain guide channel 78 for the short chain 66, and has anopening 79 to provide clearance for the drive sprocket 64. The chainguide channel 78 is part of a chain guide 80 which is identical instructure and function to the chain guide 75. The chain guide channel 78is fixed to the idler sprocket brackets 69, to the spaced apart ends ofthe flat members 60, and to the spaced apart ends of supporting angles81 extending from the respective cabinet walls. The ends of the angles57 are spaced apart to provide clearance for the idler sprocket 67.

The long chain 50 includes three pairs of lugs 82, the lugs in each pairbeing side by side so that three sets of damped lugs are provided. Thesets of lugs 82 are spaced equally around the endless chain, i.e., fiftypairs of links 73 separate each set of lugs 82. As viewed in FIG. 2 oneset of lugs 82 is shown at the drive sprocket 64 and one set of lugs 82is shown at the entrance 11, there being another set of lugs 82 directlyunderneath the set of lugs 82 shown at the entrance 1'1 and thereforeconcealed. The short chain 66 includes two pairs of lugs 83, the lugs ineach pair being side by side so that two sets of lugs are provided. Thesets of lugs 83 are spaced equally around the endless chain 66, i.e.,fifty-one pairs of links separate each set of lugs 83. As viewed in FIG.2, one set of lugs 83 is shown at each of the respective sprockets 67and 70. A fragment of the long chain 50 is shown in FIG. together withone of its lugs 82 which has a leading cam surface 84 for a purposehereinafter described. The three sets of lugs 82 and the two sets oflugs 83 are shown in FIG. 4. The lugs 82 and 83 are located as shown inFIG. 3 so that they extend above the chain guide channels 76 and 78 inposition to engage the dish racks 37, as shown in FIG. 4, and push themthrough the machine.

The drive shaft 71 carries a sprocket 85 which is driven by means of amotor 86 through an endless chain 87. The drive shaft 65 carries asprocket 88 which is driven through a similar endless chain by means ofa motor 89. Toggle switch 90 (FIGS. 1 and 6) controls both of the motors86 and 89.

An automatically operated timing system is provided to turn the prewashsolenoid 28 and the rinse solenoid 27 on and ofli, start and stop theconveyor 66 which is intermittently operated, and operate a red light 91and a green light 92 in accordance with when the machine can be fed, allin synchronism with the long conveyor chain 50 which is continuouslyoperated, the lights being mounted atop the cabinet for viewing by theoperator standing 'between the tables 35 and 36. The control buttons 23,24, 2 5, 26, 30 and 31 and the toggle switch 90 are in easy reach of theoperator as he stands between the tables. The timing system includesthree double acting switches 93, 94 and 95 for the automatic control ofthe machine which switches are hereinafter described and as shown inFIG. 4 are located on the outside of the cabinet 10 safe from thedishwasher steam and water.

The timing system further includes a pair of endless slave chains 96 and97 for operating the remotely located switches 93, 94 and 95, The slavechains 96 and 97 are exactly like the conveyor chains 50 and 66 exceptthat they have fewer links. Slave chain 96 has twenty-five pairs oflinks and slave chain 97 has fifty-one pairs of links. Slave chain 96 islocated on the outside of the cabinet 10 and runs around a suitablymounted idler sprocket 98 (FIG. 4) and a sprocket 99 (FIGS. 2 and 4) onthe drive shaft 65. Sprockets 98 and 99 are identical to the sprockets49 and 64 around which the conveyor chain 50 runs. Slave chain 97 alsois located on the outside of the cabinet 10 and runs around a suitablymounted idler sprocket 100 (FIG. 4) and a sprocket 101 (FIGS. 2 and 4)on the drive shaft 71. Sprockets 100 and 101 are identical to thesprockets 67 and 70 around which the conveyor chain 66 runs. Hence,operation of the conveyor chains 50 and 66 causes operation of therespective slave chains 96 and 97, the directions of chain travel beingindicated by the arrows in FIG. 4.

The slave chain 96 carries a single lug 102 which is like the lugs 82and 83 on the conveyor chains. However, whereas the lugs 82 and 83 arearranged in pairs, the lug 102 is a single lug. The double actingswitches 93 and 94 are suitably mounted on the outside of the cabinet 10in position to be operated by the lug 102 when the slave chain 96 moves.Since the sprockets for the slave chain 96 are the same size as thesprockets for the conveyor chain 50 and since the slave chain 96 is likethe conveyor chain 50 except for a difference ,in

length, the chains 96 and 50 travel at the same linear speed. Since theslave chain 96 has 25 pairs of links and the conveyor chain 50 has 150pairs of links, the slave chain 96 makes six revolutions for everyrevolution of the conveyor chain 50. The slave chain 97 carries twosingle lugs 103 and 104 spaced therealong which are like the slave chainlug 102. The double acting switch is suitably mounted on the outside ofthe cabinet 10 in position to be operated by the lugs 103 and 104 whenthe slave chain 97 moves. Since the sprockets for the slave chain 97 arethe same size as the sprockets for the conveyor chain 66 and since theslave chain 97 is like the conveyor chain 66 except for a difference inlength, the chains 97 and 66 travel at the same linear speed. Since theslave chain 97 has 51 pairs of links and the conveyor chain 66 has 102pairs of links, the slave chain 97 makes two revolutions for everyrevolution of the conveyor chain 66. The intermittently operatedconveyor chain 66 is run faster than the continuously operated conveyorchain 50 so that the conveyor chain 66 has time to stop and wait for adish rack 37 to be delivered to it by the conveyor chain 50. The timingsystem synchronizes the conveyor chains.

A timing control circuit for the machine is shown in FIG. 6. Closing ofthe toggle switch 90 in a lead 105 causes current to flow through themotor 89 for the long conveyor chain 50 and to flow through the motor 86for the short conveyor chain 97 provided normally open relay contacts106 in a lead 107 are closed, the relay contacts 106 being operated by arelay 108 in a lead 109. The toggle switch 90 also is an on and offswitch for the rest of the circuit. In one of its operating positions,the double acting switch 93 completes a circuit through a lead 110 tothe red light 91 and the prewash solenoid 28 from one side of the powerline to the other, and, in the other one of its operating positions, thedouble acting switch 93 completes a circuit through a lead 111 to thegreen light 92 from one side of the power line to the other. In one ofits operating positions, the double acting switch 94 completes a circuitthrough the lead 109 to the relays 27 and 108 from one side of the powerline to the other, and, in the other one of its operating positions, thedouble acting switch 94 opens such circuit and comes to rest on a deadterminal 112. In one of its operating positions, the double actingswitch 95 completes a circuit through a lead 113 to the solenoids 27 and108 from one side of the power line to the other, and, in the other oneof its operating positions, the double acting switch 95 opens suchcircuit and comes to rest on a dead terminal 114.

In a first revolution of the slave chain 96, the lug 102 carried by suchchain operates the switches 93 and 94 and positions their contacts asshown in FIG. 6, and in a second revolution of the slave chain 96, thelug 102 again operates the switches 93 and 94 but this time moves theircontacts to the other positions indicated in FIG. 6. In each revolutionof the slave chain 97, the lugs 103 and 104 carried by such chainoperate the switch 95 twice to first position its contacts as shown inFIG. 6 and then move its contacts to the other position indicated inFIG. 6.

In operation, the operator feeds racks of dishes from the front of themachine into the entrance 11 and onto the rectangularly shaped entranceframe (angles 46 and 47) where they are engaged by lugs on thecontinuously running long conveyor chain 50 which pushes them onto andthen along the rollers 55 through the long leg 12 of the cabinet 10 andonto the rectangularly shaped transfer frame (angles 57 and 58).Automatic transfer occurs by the short conveyor chain 66 starting up andengaging the racks with its chain lugs and pushing the racks onto andthen along the rollers 61 and out of the exit 13. The automaticallyoperated timing system turns the prewash and the final rinse on and 011,starts and stops 7 the short conveyor chain 66 and operates the red andgreen lights 91 and 92 in accordance with when the machine can be fed.

To start the machine, the operator pushes the start wash button 23, thestart rinse button 25 and moves the toggle switch 90 to its closedposition shown in FIG. 6. This starts the recirculating wash and rinsewhich run continuously and motor 89 which drives the long conveyor chain50 continuously. The apparatus is shown in FIGS. 2 and 4 with the shortconveyor 66 in its stopped position wherein it waits for a dish rack,the long conveyor 50 so positioned that none of its lugs 82 are inposition to obstruct movement of a rack being pushed into the entrance11, the slave chain lug 102 in a position such that switch 93 has justbeen operated to its contact position shown in FIG. 6 (green light 92on, red light 91 off and prewash solenoid 28 deenergized) and switch 94is just being operated to its contact position shown in FIG. 6(solenoids 27 and 108 energized), and the slave chain lug 104 in aposition such that switch 95 is just being operated to its contactposition shown in FIG. 6. The green light 92 being on is a signal to theoperator that he can push a rack into the machine without engaging theside of one of the chain lugs 82 and without getting sprayed withprewash water. A movement of twenty five links of the chain 50 from itsposition shown in FIGS. 2 and 4 puts a pair of chain lugs 82 in positionready to obstruct movement of a rack into the machine. However, by thattime the slave chain 96 has made a complete revolution to reoperate theswitch 93 to deenergize the green light 92 and to energize the red light91 and the prewash solenoid 28. The red light 91 warns the operator notto feed a rack into the machine and the energized prewash solenoid 28turns the prewash water on. Hence, during each revolution of theconveyor chain 50 there are three equal intervals during which lugs 82obstruct the entrance 11 and three equal intervals during which lugs 82do not obstruct the entrance 11, the respective obstructing andnon-obstructing intervals following each other in succession. Duringsuch single revolution of the conveyor chain 50, the slave chain 96makes six revolutions to operate the switch 93 six times, i.e., threetimes to one of its positions and three times to the other of itspositions shown in FIG. 6, to turn the green light 92 on and the redlight 91 and the prewash solenoid 28 ,off when the lugs 82 are innon-obstructing position and the green light 92 off and the red light 91and the prewash solenoid 28 on when the lugs 82 are in obstructingposition. Accordingly, the long conveyor chain 50 runs continuously topick up racks pushed into the entrance 11 and move them to the transferframe 56, the dishes being sprayed at the entrance 11 by theautomatically and intermittently operated prewash and the operator beingsignaled by the automatically and intermittently operated signal lightswhen he should or should not feed racks into the entrance 11.

The apparatus is shown in FIGS. 2 and 4 with the short conveyor chain 66in its stopped position wherein it waits for a dish rack and the longconveyor chain 50 in a position wherein the'set of lugs 82 at thesprocket 64 has just pushed a rack onto the transfer frame 56 whereautomatic transfer from one conveyor chain to the other occurs, a set oflugs 83 on the short conveyor chain 66 being located at the sprocket 67ready to engage the rack upon the transfer frame 56. During each singlerevolution of the conveyor chain 50, the slave chain 96 makes sixrevolutions to operate the switch 93 six times as described above andalso to operate the switch 94 six times. In the position of theapparatus as shown in FIGS. 2 and 4, the switch 94 is just beingoperated to its contact position shown in FIG. 6 (solenoids 27 and 108energized). Energization of the solenoid 108 causes its normally opencontacts 106 to close energizing the motor 86 which runs and drives theshort conveyor chain 8 66 and energization of the solenoid 27 causesfinal rinse water to spray. Hence, the short conveyor chain 66 isstarted up three times by every six revolutions of the slave chain 96,i.e., three revolutions of the slave chain 96 causes the contacts ofswitch 94 to be on the dead terminal 112 and three revolutions of theslave chain 96 causes the contacts of switch 94 to complete the circuitto the solenoids 27 and 108. The set of lugs 83, at the sprocket 67, onthe short conveyor chain 66 engages the rack upon the transfer frame 56when the short conveyor chain 66 moves and pushes the rack out of theexit 13. Switch 94 is used to start the short conveyor chain 66 and thefinal rinse but not to stop them, switch having the function of stoppingthe conveyor chain 66 and the final rinse.

Provided the operator is feeding a rack into the machine every time thatthe green light 92 comes on, the long conveyor chain 50 delivers threeracks to the short conveyor chain 66 during each revolution of the longconveyor chain. Every time that a rack is so delivered, as describedabove, the short conveyor chain 66 and the final rinse are started up bythe completion of the circuit to the solenoids 27 and 108. That is,every time that the long conveyor chain 50 completes one third of arevolution the short conveyor chain 66 and the final rinse are startedup. However, every time that the long conveyor chain 50 completes onethird of a revolution the switch 94 is operated twice by the slave chainlug 102 which attempts to cause the solenoids 27 and 108 to bedeenergized before the short conveyor 66 has completed pushing the rackout of the exit 13. Accordingly, switch 95 and its lug operatorsprovided to keep the short conveyor chain 66 going and the rinsesolenoid 27 energized until the respective rack has been pushed out ofthe machine. The short conveyor chain 66 always is stopped with one ofits two sets of lugs 83 positioned as shown in FIGS. 2 and 4.

The apparatus is shown in FIGS. 2 and 4 with the slave chain lug 104 ina position such that switch 95 is just being operated to its contactposition shown in FIG. 6 (contact of switch 95 on dead terminal 114).When the short conveyor chain 66 starts, the slave chain 97 also startscarrying the lug 103 into engagement with the switch 95 before theoperation of switch 94 can stop the short conveyor chain 66 by openingthe circuit to the solenoid 108. Operation of the switch 95 moves itscontacts to close the circuit through the lead 113 to maintain thecircuit to the solenoids 27 and 108 closed after switch 94 opens thecircuit to the solenoids 27 and 108 through the lead 109. Shortlythereafter slave chain lug 104 reoperates the switch 95 positioning thecontacts of the switch 95 on the dead terminal 114. This causesdeenergization of the solenoids 27 and 108 and the final rinse and theshort conveyor chain 66 stop. Since the short conveyor chain 66completes one revolution for every two turns of the slave chain 97 andsince the slave chain lug 104 is positioned as shown in FIG. 4 at theswitch 95 to stop the short conveyor chain 66 when the chain lugs 83 areat the respective sprockets 67 and 70, the short conveyor chain 66always stops as shown in FIGS. 2 and 4 with a set of its lugs 83 at thesprocket 67 and waits for the continuously moving conveyor chain 50.

To summarize the automatic timing operation, the continuously movingconveyor chain 50 delivers the racks to the intermittently movingconveyor chain 66. Every time that the long conveyor chain 50 turnsonce, its slave chain 96 turns six times to operate switches 93 and 94six times. Six operations of switch 93 turns the green light 92 on andat the same time the red light 91 and the prewash solenoid 28 off threetimes, and the red light 91 and the prewash solenoid 28 on and at thesame time the green light 92 off three times. The green light being onis a signal to the operator that the prewash Spray Off 1 .4 tha th chainlugs 82 are in non-obstructing positions and, hence, that it is time tofeed a rack into the entrance 11. Six operations of switch 94 starts theshort conveyor 66 and the final rinse three times to to take away andfinally rinse the dishes in the possible three racks delivered by thelong conveyor chain 50 during such single revolution.

Every time that the short conveyor 66 starts its slave chain 97 startsand makes one revolution, the slave chain leg 103 operating the switch95 to keep the short conveyor chain 66 and the final rinse going afterthey otherwise would have been stopped by the operation of the switch94, and the slave chain lug 104 reoperating the switch 95 to stop theshort conveyor chain 50 in its position shown in FIG. 4 whereupon theslave chain 97 also stops in its position shown in FIG. 4.

It sometimes happens that the dish racks 37 are a little too large tofit in the transfer frame 56 or the dish racks 37 are moved into suchframe in a cocked position. In order to prevent a jam up of the longconveyor chain 50 in such situations, the leading edges 84 (FIG. 5) ofthe lugs 82 are cam-shaped so that the lugs 82 lift the racks up enoughto leave room for such lugs to escape as they move downwardly around thedrive sprocket 64.

A modified machine is shown in FIGS. 7 and 8. Reference numbers in FIGS.7 and 8'which are similar to numbers in FIGS. 1-6 refer to parts alikein structure and function. The threshold channel 45a is provided with ahole 115 which receives a ring-shaped gasket 116 which in turn receivesa plunger 117 of a solenoid 118 that is carried by a bracket 119 fixedto the threshold channel 45a. The solenoid 118 is wired into the lead110 (FIG. 6) in place of the red light 91 or it is wired into the lead110 in series with the red light 91. The circuit shown in FIG. 6 thenfunctions as hereinbefore described except that, in the case where thesolenoid 118 is substituted for the red light 91, completion of thecircuit through the lead 110 instead of lighting the red light 91 towarn the operator energizes the solenoid 118 which moves its plunger 117into its broken line position shown in FIG. 8 to prevent the operatorfrom pushing a dish rack into the entrance of the machine, i.e., a lockor stop means is provided in place of a signal light, and in the casewhere the solenoid 118 is placed in series with the red light 91,completion of the circuit through the lead 110 instead of just lightingthe red light 91 energizes both the red light 91 and the solenoid 118 toboth warn the operator and prevent the operator from pushing a dish rackinto the entrance of the machine, i.e., both a lock or stop means and asignal light are provided.

It is to be understood that the above description is illustrative ofthis invention and that various modifications thereof can be utilizedwithout departing from its spirit and scope.

Having described the invention, we claim:

1. A conveyor dishwashing machine comprising, in combination, anL-shaped cabinet defining a wash space and having two joining legs thefirst of which defines an entrance and the second of which defines anexit at the ends of the respective legs, an entrance frame within thewash space at the entrance upon which dish racks are placed, spray meanswithin the wash space for spraying liquid onto articles in the dishracks, a transfer frame at the junction of the legs, track means betweenthe frames and between the transfer frame and the exit, the frames andthe track means being so arranged that dish racks can be moved from theentrance frame along the respective track means to the transfer frameand from the transfer frame along the respective track means to theexit, conveyor means one in each leg of the L for moving dish racksthrough the leg of the L defining the entrance continuously and formoving dish racks through the other leg of the L intermittently, theconveyor means comprising lug means for moving racks placed upon theentrance frame along the respective track means to the transfer frameand from the transfer frame along the respective track means to theexit, signal means, spray operating means for turning the spray means onand off, and control means for keeping the conveyor means synchronizedand for automatically operating the signal means and the spray operatingmeans in accordance With the position of the lug means of thecontinuously operable conveyor means relative to the entrance.

2. A conveyor dishwashing machine according to claim 1 wherein theentrance and the exit both open from the front and tables are sojuxtaposed to the entrance and the exit that the path of travel of theracks to, through and from the cabinet is in the shape of a U.

3. A conveyor dishwashing machine comprising, in combination, anL-shaped cabinet defining a wash space and having two joining legs thefirst of which defines an entrance and the second of which defines anexit at the ends of the respective legs, an entrance frame within thewash space at the entrance upon which dish racks are placed, spray meanswithin the wash space for spraying liquid onto articles in the dishracks, a transfer frame at the junction of the legs, track means betweenthe frames and between the transfer frame and the exit, the frames andthe track means being so arranged that dish racks can be moved from theentrance frame along the respective track means to the transfer frameand from the transfer frame along the respective track means to theexit, conveyor means one in each leg of the L for moving dish racksthrough the leg of the L defining the entrance continuously and formoving dish racks through the other leg of the L intermittently, theconveyor means comprising lug means for moving racks placed upon theentrance frame along the respective track means to the transfer frameand from the transfer frame along the respective track means to theexit, stop means for obstructing the entrance when the lug means of thecontinuously operable conveyor means obstructs transverse movement ofracks on the entrance frame, spray operating means for turning the spraymeans on and off, and control means for keeping the conveyor meanssynchronized and for automatically operating the stop means and thespray operating means in accordance with the position of the lug meansof the continuously operable conveyor means relative to the entrance.

4. A conveyor dishwashing machine according to claim 3 wherein theentrance and the exit both open from the front and tables are sojuxtaposed to the entrance and the exit that the path of travel of theracks to, through and from the cabinet is in the shape of a U.

References Cited by the Examiner UNITED STATES PATENTS 2,139,877 12/1938Brandt 198-23 2,328,050 8/1943 Bullard 134-67 2,671,455 3/1954 MacDonald134113 2,966,914 1/1961 Sadwith 134-68 SAMUEL F. COLEMAN, PrimaryExaminer. RICHARD E. AEGERTER, Examiner.

1. A CONVEYOR DISHWASHING MACHINE COMPRISING, IN COMBINATION, ANL-SHAPED CABINET DEFINING A WASH SPACE AND HAVING TWO JOINING LEGS THEFIRST OF WHICH DEFINES AN ENTRANCE AND THE SECOND OF WHICH DEFINES ANEXIT AT THE ENDS OF THE RESPECTIVE LEGS, AN ENTRANCE FRAME WITHIN THEWASH SPACE AT THE ENTRANCE UPON WHICH DISH RACKS ARE PLACED, SPRAY MEANSWITHIN THE WASH SPACE FOR SPRAYING LIQUID ONTO ARTICLES IN THE DISHRACKS, A TRANSFER FRAME AT THE JUNCTION OF THE LEGS, TRACK MEANS BETWEENTHE FRAMES AND BETWEEN THE TRANSFER FRAME AND THE EXIT, THE FRAMES ANDTHE TRACK MEANS BEING SO ARRANGED THAT DISH RACKS CAN BE MOVED FROM THEENTRANCE FRAME ALONG THE RESPECTIVE TRACK MEANS TO THE TRANSFER FRAMEAND FROM THE TRANSFER FRAME ALONG THE RESPECTIVE TRACK MEANS TO THEEXIT, CONVEYOR MEANS ONE IN EACCH LEG OF THE L FOR MOVING DISH RACKSTHROUGH THE LEG OF THE L DEFINING THE ENTRANCE CONTINUOUSLY AND FORMOVING DISH RACKS THROUGH THE OTHER LEG OF THE L INTERMITTENTLY, THECONVEYOR MEANS COMPRISING LUG MEANS FOR MOVING RACKS PLACED UPON THEENTRANCE FRAME ALONG THE RESPECTIVE TRACK MEANS TO THE TRANSFER FRAMEAND FROM THE TRANSFER FRAME ALONG THE RESPECTIVE TRACK MEANS TO THEEXIT, SIGNAL MEANS, SPRAY OPERATING MEANS FOR TURNING THE SPRAY MEANS ONAND OFF, AND CONTROL MEANS FOR KEEPING THE CONVEYOR MEANS SYNCHRONIZEDAND FOR AUTOMATICALLY OPERATING THE SIGNAL MEANS AND THE SPRAY OPERATINGMEANS IN ACCORDANCE WITH THE POSITION OF THE LUG MEANS OF THECONTINUOUSLY OPERABLE CONVEYOR MEANS RELATIVE TO THE ENTRANCE.